As computer technologies advance, mobile terminals, such as mobile phones, perform more and more powerful functions, such that mobile terminals are indispensable in people's daily life. Various parts of a mobile terminal generally need to transmit data to a processor thereof, via two paths of level signals. Hereinafter, the course of transmitting data by the parts to the processor is given by using a camera as an example.
In the prior art, after a camera of a mobile terminal picks up an image, the camera generally needs to transmit image data to the processor. The processor processes the received image data. Data is transmitted between the camera and the processor of the mobile terminal generally by using Mobile Industry Processor Interface (MIPI) protocol. Each time data is transmitted, the level signals transmitted by the camera may be categorized into a plurality of stages in terms of time sequence, which are respectively an LP-11 stage (a control mode stage), an LP-01 stage (a high-speed request stage), an LP-00 stage (a preparation stage), an HS-0 stage (a reception waiting stage), and a data transmission stage. In the LP-11 stage, the two paths of level signals are both at a high level; in the LP-01 stage, one of the two paths of level signals is at a high level and the other is at a low level; in the LP-00 stage, the two paths of level signals are both at a low level; in the HS-0 stage, the voltages of the two paths of level signals are increased to be within a voltage range of differential signals to form differential signals; and in the data transmission stage, the two paths of level signals remain in the state of the differential signals for data transmission.
Generally, during the course of data transmission, a time duration of the LP-00 stage may be changed due to signal line impedance. A waiting time duration may be preconfigured in the processor. After the processor begins to receive data, it detects when an input signal changes from the LP-01 stage to the LP-00 stage. That is, it detects that one of the two paths of level signal remains at a low level and the other is changed from a high level to a low level. After a preset waiting time duration from the point of entering the LP-00 stage, the processor starts detecting a start point of the HS-0 stage. That is, it detects that the voltages of the two paths of level signals are increased to be within the voltage range of the differential signals. Upon detection of the start point, the processor waits for a preset time duration of the HS-0 stage to run, before it starts detecting data on the differential signals, so as to obtain the data transmitted by the camera. Based on the MIPI protocol, the above waiting time duration needs to be within a range of a standard time duration stipulated by the MIPI protocol. Further, the time duration from the end of the waiting time duration to the start of the HS-0 stage also needs to be within a range of a standard time duration stipulated by the MIPI protocol, such that the processor can correctly receive data.
Based on the basic principles of the above-described data transmission, a person skilled in the art generally tests a plurality sample terminals of the same model for setting a waiting time duration of a processor. A time duration of the LP-00 stage of the signals received by the processor of each terminal is measured using an oscilloscope to calculate an average value of the time durations. A person skilled in the art then uses a time duration obtained by dividing the average value by two as the preset waiting time duration of the mobile terminals of the model.
During implementation of the present disclosure, the inventors have identified at least the following drawbacks in the related technologies.
A person skilled in the art uses half of the average value of the time durations of the LP-00 stage of a plurality of sample terminals as the waiting time duration of the processor. Because of mass production of the mobile terminals, time durations of the LP-00 stage of level signals received by processors of different mobile terminals may vary greatly. In addition, while the mobile terminals are used, line impedance in the mobile terminals may be changed due to various reasons, such that the time durations of the LP-00 stage of the level signals received by the processors may be changed accordingly. Since each mobile terminal is given a fixed waiting time duration, in some mobile terminal, the time duration from the end of the waiting time duration to the start of the HS-0 stage may not be within the range of the standard time duration stipulated by the MIPI protocol. Consequently, the data read by the processor may be incorrect.